1. Field of the Invention
This invention pertains to handheld computers and accessory devices for handheld computers. More specifically, embodiments of this invention encompass a handheld computer with an ESD protective connector.
2. Description of the Related Art
Handheld computers use peripheral or accessory devices to enhance their abilities and functions. Typical accessory devices for handheld computers include communication cradles or docking stations, battery chargers, Universal Serial Bus (USB) devices, and modems. Generally, these devices are adapted to mate with the handheld computer using either wiping style connectors or pogo style connectors.
Until now, handheld computers were adapted to connect with accessory devices having either a wiping style or a pogo pin connector. During or after the mating process with either connector, a static electric discharge or electrostatic discharge event (EDE) can occur that can damage electronic components in the handheld computer. The static electric discharge occurs due to the buildup of static electricity on the accessory device, the user or the handheld computer. The voltages that drive an electrostatic discharge can be significant. In fact, when the humidity drops below 50% Rh, the human body can acquire and dissipate an electrostatic charge having a potential in excess of 30,000 volts. Unfortunately, many devices are susceptible to ESD damage at relatively low voltages e.g. less than 100 Volts. In fact, a discharge of only 10 Volts can destroy some types of devices.
The microelectronics of a handheld computer are particularly sensitive to damage from electrostatic discharge or ESD. This due to fact that these components are composed of micro-miniature traces and structures of alternating layers that may be insulative, conductive or semi-conductive. Rapid electrostatic discharge can cause damage to these underlying structures via the traces of the component. Thus static electricity can readily damage integrated circuits containing such traces including, microprocessors, ASICS and memory devices including RAM and ROM devices. The damage can range from erasure of memory registers and contents to physical damage of the circuits due to damage of the traces.
Handheld computers are also susceptible to such discharges. For example, when the interface connector of the handheld computer is unmated, the electronic components that are connected to this unmated connector are susceptible to receiving, through the conductive pins of the unmated connector, an electrostatic discharge current from an electrostatically charged human or other sources of an electrostatic charge. Similarly, during or after the mating process of the connector to accessory device, electrostatic current can flow from the accessory device the hand-held computer, causing damage to internal components of the handheld computer.